Between 100 to 200 employees of Air Serv, which cleans Delta planes at Terminal D, went on strike at 10 p.m. and will return to work for the Thursday night shift at 6:30 p.m., according to 32BJ Service Employees International Union.

Workers earlier this year voted for SEIU’s representation but the company has yet to bargain with them, 32BJ spokeswoman Amity Paye said.

Picketing employees represented a majority of the workforce, according to Paye, though she conceded that Air Serve has brought in a handful of replacements for the day.

Reps for Delta and Air Serv could not be immediately reached for comment on Thursday.

Even though Terminal D only services domestic Delta flights, many international travelers still connect through LGA, the union said.

“Ebola is the word of the day but the workers are scared (of various work conditions) for many other reasons,” Paye said.